d&b TI 385 d&b Line array design - Manual (Page 11)

Q1/Q-SUB/J-SUB crossover setup
Please note that a combined ground stack consisting of
Q-SUB and J-SUB cabinets will only provide a consistent
directivity when Q-SUBs are used in CSA setups. Also make
sure to keep the required distance of 60 cm (2 ft) between
the stacks in order to not adversely affect the cardioid
directivity of the systems.
J-SUB subwoofers can also be used as an alternative to
ground stacked Q-SUBs. In this case J-SUB cabinets are
operated in standard mode with a crossover frequency of
100 Hz. One J-SUB will replace three Q-SUB cabinets in a
CSA setup and extends the system bandwidth down to
32 Hz.
Q1/J-SUB crossover setup
J-SUB cabinets in INFRA mode can be used to extend the
bandwidth of a Q1 line array operated in full-range mode,
without Q-SUBs. As this application does not expand the
headroom of the Q1 array it is only useful when medium
levels but very low frequencies are required, for example
for special effects.
Q1/J-SUB crossover setup, full range
J-INFRA (27 – 60/70 Hz)
To achieve the ultimate low frequency extension for a Q
system consisting of Q1 and Q-SUB cabinets, additional
J-INFRA subwoofers can be used. They provide a standard
(60 Hz) and a 70 Hz mode. The selection of the mode
depends on the coupling between J-INFRA and Q-SUB
cabinets in the actual setup. When combined in a ground
stack the standard (60 Hz) mode provides more headroom
at very low frequencies.
Please note that a combined ground stack consisting of
Q-SUB and J-INFRA cabinets will only provide a consistent
directivity when Q-SUBs are used in CSA setups. Also make
sure to keep the required distance of 60 cm (2 ft) between
the stacks in order not to adversely affect the cardioid
directivity of the systems.
Q1/Q-SUB/J-INFRA crossover setup
TI 385 (6.0 EN) d&b Line array design, ArrayCalc V8.x Page 11 of 54